Chris Mooney - The Dead Room

Sitting on the dashboard was a device that resembled a police scanner.

'I've tried enhancing the picture from different angles,' Castonguay said, 'but I can't get a lock on his face. But see this shadow here?' He pointed to the area between the two front seats. 'This may or may not be part of a leg and an arm. I'll need more time to enhance it.

'That's all I have. I'll have printouts of the pictures to show you in another hour or so. Just do me one favour. When you get your hands on this camera, you're to let me know immediately. I'm dying to play with it.'

'You got it.'

Three men were interested in Amy Hallcox and her son – the black-haired man who had posed as a Fed, the cameraman and the bald driver. Had they been the men she'd seen in the woods last night?

She thought back to the picture of what might be another person sitting in the back of the van. A fourth man. Were there more? How many people were following her? Darby opened the door of the fingerprint suite. Coop, wearing safety glasses and blue latex gloves, was hunched over a lab bench examining a bullet. He had already tried dusting it for prints.

She saw the bullet's pitted nose and knew what it was: a hollow-point round. The same ammo had killed her father.

'It's a nine-millimetre Parabellum round,' Coop said. 'I found it in the kitchen, underneath an overturned sideboard. Someone must have dropped it.'

'Any prints?'

He shook his head.

'We could fume it with cyanoacrylate,' she said. 'If the Super Glue finds a print, we can try using different luminescent stains, then enhance it in the VMD unit.' Vacuum Metal Deposition, she knew from experience, yielded better-looking latent prints.

'I'm going to try something else first.' Coop picked up the shell casing with a pair of tweezers and placed it on a circular metal dish that sat underneath a probe.

Darby looked over his shoulder. Her jaw dropped.

'Is that a scanning Kelvin probe?'

'It is,' he said. 'Jesus, I haven't seen you this excited since the last time U2 came through Boston.'

She placed the bag holding Amy Hallcox's fingerprint card on the bench beside them, dimly aware that the usual humour was absent from his voice. Her attention was on the probe. She had read about it but had never seen a real-life demonstration of one.

'How did you get your hands on it?'

'This unit is courtesy of my new friends in London,' he said. 'Do me a favour and turn on that monitor.'

She did and then pulled out a chair and watched Coop adjust the controls of a small device resembling a futuristic microscope. Human sweat dried fairly quickly. What lingered was a mix of organic and inorganic compounds. Was Coop suggesting that these compounds and chemicals could be detected by this probe?

'What sort of developer are you going to use?'

'You don't need to use a chemical or a powder.'

'Then how are you going to find a latent print?'

'The beauty of this new technology, Darb, is that once you touch metal with your bare fingers, the inorganic salts from your skin corrode the shell casing – you "brand" your print on to the metal. You can't wipe it away.'

'What if a shell was fired? The heat would destroy the organic compounds left behind – amino acids, glucose, peptides and lactic acid.'

'Doesn't matter. The probe can retrieve prints from fired shells, even detonated bomb fragments, where temperatures can reach as high as five hundred degrees Celsius. The Kelvin probe uses voltage to examine the surfaces where a fingerprint may have been deposited.'

'So what you're suggesting is that no matter what, you can't wipe away a fingerprint.'

'Exactly.' He pressed a button on a small box attached to the probe. 'Watch the monitor.'

Darby saw a magnified image of the bullet on the screen. 'Looks like you've got something.'

Coop studied the faint, spidery lines of a partial latent fingerprint on the monitor.

'I'm going to have to create what's called a voltage map,' he said. 'It's a three-dimensional rendering of the latent print. It will take a couple of hours. How'd the autopsy go?'

'They're doing it right now.' Darby's attention had shifted back to the hollow point lying on the dish.

'Did you examine the body?'

She nodded, then said, 'Would a scanning electron microscope destroy or alter the fingerprint in any way?'

'No.'

'Then before you do the voltage map, I want to borrow the bullet for a moment and take a closer look at the cartridge's headstamp. It doesn't look right.'

Coop, using tweezers, picked up the bullet for a closer look.

'I don't see anything unusual.'

She pointed to the round metal base. 'The spark plug looks smaller than normal, don't you think?'

He shrugged, then pushed his chair away from the table. 'Go for it.'

Darby picked up the dish holding the bullet and carried it across the room to the lab's brand-new scanning electron microscope. She loaded the cartridge into the chamber, shut the small door and then sat down, turning her attention to the console. Coop wheeled a chair next to hers.

The SEM's terminal screen showed a magnified black-and-white image of the bullet's headstamp. A thick white ring glowed in the middle, around the primer cap. Printed in the centre were two neat rows containing both letters and numbers:

'What the hell is that?' he asked. 'Some sort of stamp?'

'That's exactly what it is.' She printed off two copies of the image, then created a digital copy and sent the jpeg to her email. 'What we're looking at here is what's being hailed as the latest technological advance in ballistics identification – microstamping.'

'That technology hasn't made its way into mass production.'

Darby nodded. 'At the moment, the gun lobbyists have successfully prevented microstamping from seeing the light of day, but that may change soon. California is trying to push through a bill that would require microstamping to be implemented on all firearms over the next five years. If the bill gets passed, it'll be the first state in the nation to have this.

'Currently, we need to find the handgun and examine it to see if a particular bullet was fired through it. Microstamping eliminates that. It creates a ballistic fingerprint. A handgun's firing pin is engraved with a unique microscopic code that stamps the gun's make, model and serial number on the primer cap. The first row – in this case, GLK18 – is supposed to be the stamp for the handgun, the bottom row the code for the shop that sold it.'

'So I'm assuming there's going to be some sort of database that'll store these numbers and codes.'

Darby nodded. 'The database gives us not only the make and model of the handgun but where it was sold, who purchased it – everything.' She worked the small joystick mounted on the keyboard in an effort to examine the edges of the cartridge's headstamp. 'And the database will also provide us with information about other crime scenes where cartridges with the same stamp were found. The beauty of this new technology is that you can see the stamp only through a scanning electron microscope.'

'But since this technology isn't in mass production yet, there's no way we can trace it.'

'This bullet has to be a part of a batch of test ammo.'

'A prototype, in other words.'

'Exactly. Only a handful of companies are doing microstamping, so this prototype or whatever it is should be easy to narrow down.'

'The stamp on this first row here, GLK18,' Coop said. 'I'm guessing it's a Glock eighteen.'

'That would be my guess too.'

'I've never heard of a model eighteen.'

'That's because they're not sold here. It's a military-issue weapon commissioned by the Austrian Counter-Terrorism Unit, EKO Cobra. As far as I know, they're the only ones who use it. Take a look at the engraved letters around the headstamp.'